Hygrothermostat



July 4, 1939. M. Q'SNEDIKER HYGROY'I'HERMOSTAT Filed March 12, 1936 a 512 edz/zer;

Marion 239'. 7 m

Patented July 4, 1939 HYGROTHEBMOSTAT Morton 0. Snedlker, Chicago, 111., assignor to The Powers Regulator Compass-Chicago, 111., a corporation of Illinois Application March 12,

Claims.

uncomfortable at a temperature of '72 with avery low moisture content of the air, while relatively comfortable at a temperature of 69 with a high moisture content. An object of my invention is,'therefore, to provide a thermostat for controling the temperature and a hygrostat directly associated therewith that serves to modify the adjustment of the thermostat according to changesin moisture condition.

In situations where means are provided for maintaining a constant relative humidity, an instrument such as herein described is not essential, but in the absence of such provision it will be found that regulation such as provided by the use of the apparatus here disclosed will contribute greatly to the comfort of the occupants.

In the instrument, the thermo-sensitive and hygro-se'nsitive elements are directly connected and associated under a single cover, thereby simplifying the mechanism by which the action of one element is modified by that of another. The particular apparatus has been designed for simplicity of operation, manufacture and assembly,

for variation in the ratio in the change of adjustm ent, and for continued operation through long periods without repairs.

The principle of operation is the reverse of that shown in the patent to Bulley, No. 1,953,923

of April 10, 1934 in which a hygrostat or "its equivalent is adjusted'by a thermostat.

' The invention will be more readily understood by reference to the accompanying drawing, in which,

Fig. 1. is a face view, with the cover removed, of an instrument such as disclosed herein, and

Fig. 2 is a vertical sectional view therethrough, the cover being shown in place.

In the drawing I have illustrated a back plate Ill and a support or base ll secured thereto and on which the various devices are. mounted. Con- 'nected to the base His an air inlet pipe l2 connected by a passage 13 to the controlling valve, indicated generally, by the numeral l4; while a passage l5 communicating with a pipe l6 leads to a valve, not shown, for regulating the supply of heat to a space. Inasmuch as this apparatus 1936, Serial No. 68,489

is old and well-known, I will not further describe it. It is sufficient to say that the pair of expansive diaphragms l'l-l8 act in unison against the force of the spring l9 to unseat the valve I4 and admit air to the pipe It for closing a heat valve. The diaphragms or belows ll-IB, constituting the thermo-sensitive element, are supported on a bar 2|), one end of which is in screwthreaded engagement with an adjusting screw 2|, by means pf which direct manual regulation of the heat is effected. At its upper end, the bar is bifurcated, the two ends being engaged by a cross piece 22, adjustably held by means of the screw 23 in the slot 24 provided in one arm 25 of a bell-crank. The bell crank is fulcrumed on a pin 26 while the other arm 21 of the bellcrank overlies the pin extensions 28-29 of the hygro-sensitive elements 30-3I. These elements may consist of wood strips, the lower ends of which are capped by the pieces 32-33, the latter being contacted by adjusting screws 34-35. These screws are seated in an equalizing bar 36 fulcrumed on the screw 31. n

It will be seen that upon an increase in the moisture content of the space to be controlled, the wood strips will elongate, thus causing the bell-crank to rock on its pivot and to apply pressure to the upper end of the bar 20, thus tending to change the adjustment of the thermosensitive element to provide for a lower temperature in the space. When an opposite moisture condition occurs, a reverse action will take place.

It will be understood that the pin M and the thread connection thereof with the lower end of the bar 20 provides for the necessary lost motion to permit the relatively very minute movement of the bar for adjustment by the hygrosensitive element.

In order to vary the ratio of adjustment of the thermo-sensitive element by the hygro-sensitive element, the cross-piece 22 is shifted longitudinally of the slot 24, thus shortening one arm and lengthening the other arm of the two levers that affect the operation.

I claim:

1. In a hygro-thermostat, the combination of a valve for controlling a supply of heat, a thermosensitive element for controlling said valve, a support for said'element, means applied to one end of said support for adjusting the position of said support, whereby to vary the effect of said thermo-sensitive element on the valve, a hygro-sensitive element mounted in juxtaposition to said thermo-sensitive element, and means for changing the endwise movement of the hygro-sensitive element into movement at right-angles thereto as applied to the other end of said support whereby to vary the adjustment of said heat-sensitive element according to moisture conditions as reflected by said hygro-sensitive element.

2. In a hygro-thermostat, the combination of a valve for controlling a supply of heat, a thermosensitive element for controlling said valve, a support for said elei'nent, means for adjusting the position of said support, whereby to vary the effect of said thermo-sensitive element on the valve, a hygro-sensitive element mounted in juxtaposition to said thermo-sensitive element, means for changing the endwise movement of the hygro-sensitive element into movement at right-angles thereto as applied to said support whereby to vary the adjustment of said heatsensitive element according to moisture conditions as reflected by said hygro-sensitive element, and means for varying the ratio of the transference of motion from one element to the other.

3. In a hygro-thermostat, the combination of a valve for controlling a supply of heat, a thermosensitive element for controlling said valve, a bar supporting said element, a screw at one end of the bar for adjusting its position, whereby to vary the effect of said thermo-sensitive element on the valve, a hygro-sensitive element mounted in juxtaposition to said thermo-sensitive element, and means for changing the end-wise movement of the hygro-sensitive element into movement at right-angles thereto as applied to the other end of said bar, whereby to vary the adjustment of said heat-sensitive element according to moisture conditions as reflected by said hygro-sensitive mo-sensitive element, a bell-crank for changing the endwise movement of the hygro-sensltive ele- .ment into movement at right angles thereto as applied to the other end of said support whereby to vary the adjustment of said heat sensitive element according to moisture conditions as reflected by said hygro-sensitive element.

5. In a hygro-thermostat, the combination of a valve for controlling a supply of heat, a thermo-sensitive element for controlling said valve, a support for said element, means for adjusting the pcsition of said support whereby to vary the eil'ect of said thermo-sensitive element on the valve, .a pair of parallel wood strips mounted alongside of said thermo-sensitive element, an equalizing bar at one end of said strips and one 'arm of a bell-crank at the other end thereof, the

other arm ofthe bell-crank acting on said support whereby to vary the adjustment of said heat sensitive element according to moisture conditions as reflected by said wood strips.

MORTON O. SNEDIKER. 

